Getting width & height of an image with filereader

You have to wait for the image to load. Try handling the element inside .onload.

I've also simplified the process of setting the source of the two elements to how you should be doing it (with jQuery).

reader.onload = (function(theFile) {     var image = new Image();    image.src = theFile.target.result;    image.onload = function() {        // access image size here         console.log(this.width);        $('#imgresizepreview, #profilepicturepreview').attr('src', this.src);    };});

For me the solution of Austin didn't work, so I present the one worked for me:

var reader = new FileReader;reader.onload = function() {    var image = new Image();    image.src = reader.result;    image.onload = function() {        alert(image.width);    };};reader.readAsDataURL(this.files[0]);

And if you find that assignment image.src = reader.result; takes place after image.onload a bit wired, I think so too.

Here's an answer inspired by Austin Brunkhorst with a callback for ascertaining image size in case you want to reuse the function elsewhere in your code.

fileControl is assumed to be a jQuery element.

function didUploadImage(fileControl) {         // Render image if file exists.   var domFileControl = fileControl[0];   if (domFileControl.files && domFileControl.files[0]) {      // Get first file.      var firstFile = domFileControl.files[0];      // Create reader.      var reader = new FileReader();      // Notify parent when image read.      reader.onload = function(e) {         // Get image URL.         var imageURL = reader.result;        // Get image size for image.        getImageSize(imageURL, function(imageWidth, imageHeight) {            // Do stuff here.        });      };      // Read image from hard disk.      reader.readAsDataURL(firstFile);      // Print status.      console.log("Uploaded image: " + firstFile.name);   }}function getImageSize(imageURL, callback) {         // Create image object to ascertain dimensions.   var image = new Image();   // Get image data when loaded.   image.onload = function() {            // No callback? Show error.      if (!callback) {         console.log("Error getting image size: no callback. Image URL: " + imageURL);      // Yes, invoke callback with image size.      } else {         callback(this.naturalWidth, this.naturalHeight);      }   }   // Load image.   image.src = imageURL;}